Circuit closer



Feb. 6, 1940.

F. M. BLUM CIRCUIT CLOSER Filed March 29, 1937 FIG.'2.

FIGQB.

42W 4.. G 13 W-HPHTL m HHI INVENTOR FRANK M. BLUM AT TORNEYS PatentedFeb. 6, 1940 UNITED STATES PATENT OFFlCE Harnischfeger Corporation,

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corporation of Wisco Milwaukee, Win, a

Application March 29, 1937, Serial No. 133,522

1 Claim.

The invention relates to circuit closers.

The main object of the invention is to provide a circuit closure forcontrolling a plurality of electrical circuits which are successivelymade or broken by the reciprocatory movement of a single plunger memberunder the control 01 the operator. More particularly the inventionincludes an insulating casing having contact bars of different lengthsmounted therein and a plunger carrying a series of ball contacts adaptedto engage said bars, said balls also being in constant contact with acommon conductor mounted on said plunger.

The invention further consists in the several features hereinafter setforth and more particularly defined by the claim at the conclusionhereof.

In the drawing:

Fig. 1 is an elevation view of a circuit closer embodying the invention,parts being broken away and shown in section along the line l-l of Fig.2;

Fig. 2 is a detail horizontal sectional view taken on the line 2-2 ofFig. 1;

Fig. 3 is a detail horizontal sectional view taken on the line 3-3 ofFig. 1;

Fig. 4 is a wew of a wiring diagram including the circuit closer;

Fig. 5 is a top of the plunger;

Fig. 6 is an expanded view of parts of the plunger head, one of theparts being shown in section, the section being taken along the brokenline 6i of Fig. 3, the other part being shown in dotted lines.

Referring to the drawing, the numeral 1 designates a base of suitableinsulating material, 8 a housing of insulating material mounted on saidbase and secured thereto by clamping screw bolts 9, and 10 a plunger ofsuitable insulating material having a round shank ll working in anopening @2 in the housing and a head 13 carrying a piurality of contactshereinafter described.

The housing 8 has a hollow hexagonal interior H providing six side wallsin each of which a contact plate I5 is inset and secured by a clampingscrew l6 which passes through an opening H in each wall and cooperateswith a screw l8 in threaded engagement with the threaded bore 38 in thescrew IE to form a binding post for one of the circuit wires. The platesi5 are shown in Fig. 4 and numbered I to 6, all of the plates except Iand 2 being of different lengths.

plan view of one of the parts The head I3 of the plunger has aninternally threaded metal insert 20 about which it is cast providing ananchorage for a holding screw 2| which secures an auxiliary hexagonalhead member 22 the screw engaging a metal insert 23 in said member 22 tosecure it for movement with the head part IS. The head part l3 has ahexagonal portion slidably fitting the walls 01 the housing 3 andprovided with an annular surface 24 providing a seat for a contact plate25 and provided with six hexagonally spaced depending nibs 0r tongues23.

The head part l3 has a cylindrical bottom portion 21 provided with aconical end 28, and these parts flt into a similar cavity 29 formed inthe head part 22. The sides of the cavity 29 are not continuous but areintercepted by inclined grooves 30 whose axes are located in planesnormal to the side walls or the head member 22. The side walls of themember 22 are provided with centraliydisposed longitudinally extendinggrooves 3! which merge with radially extending top grooves 32 whoseinner ends 33 are of reduced width as shown in Fig. 3, the grooves 32and 33 cooperating to form pockets for the contact balls 3| and theinclined grooves 30 extending to the grooves 32 and cooperating with theconical end 28 and insert 23 to form pockets for the coil springs 35,each of which engages a ball 34 and forces it upwardly against thecontact plate 25 and at the same time yieldingly presses the balllaterally so that it will engage the side wall of the housing and thecontact plate l5 associated therewith. The balls in their outwardposition engage the tongues 26 which also assist in holding the balls intheir pockets during the assembly of the device.

The grooves 3| are almost as wide as the plates i5, and the slidingconnection between the housing and the head part 22 is made at the partsof said head member facing the corners of said housing.

The plunger is normally held in an upper of! position by a spring 36interposed between the head thereof and the base i.

The balls 34 are always in contact with the plate 25 and hence always incircuit with each other, and as shown in Fig. 4 when the plunger ismoved downwardly, the balls for the plates i and 2 are first engagedwhich acts to estab lish a circuit from a current supply conductor 31through conductor 38, plates I, 25, and 2, conductor 39 through anelectroresponsive deof insulating material to it, the head of 5 vice l0,conductor Ii to the other supply wire 41. Similarly as the plunger ispressed further inwardly, the supply circuit from the plate I issuccessively connected to the electroresponsive devices 43, 44, N, and40 connected in circuit with the plates 3, 4, I, and l and the conductor42. Thus the devices 40, 43, ll, ll, and 46 are successively energizedto control circuits to other electrical apparatus. Conversely thegradual release of the spring pressure on the plunger causes it to moveupwardly to suecessively cut out the control circuits. Theseelectroresponsive devices may be of various kinds, such aselectromagnetic contactors tor establishing circuits or greater currentcarrying capacity than those controlled by the device described herein.

With this device as the balls 34 are always yieldingly engaged with thecontact plate 2! and yieldingly engage the plates II as they move overthem, good circuit connections are and the springs do not take thecurrent.

assured I desire it to be understood that this invention is not tobelimited to any particular or specific arrangement of parts except in sofar as such limitations are included in the claim.

What I claim as my invention is:

In a circuit closer, the combination or a hollow housing of insulatingmaterial having a polygonal interior, a plunger reciprocating in saidhousing 'and having a two-part head of insulating ma-

